In an Electric Power Steering (EPS) unit an electric motor drives a worm shaft and worm gear to provide assist torque to the turning of a steering shaft. This reduces the effort required to steer a vehicle. In certain applications, worm shaft bearings with axial lash are axially preloaded. This prevents or limits axial travel of the worm shaft to provide improved vehicle steering response.
However, adding axial preload forces to the worm shaft bearings with axial lash often imparts additional frictional forces for the worm shaft bearings and the steering system.
Accordingly, it is desirable to provide a worm shaft subassembly capable of imparting a greater preload to the worm shaft without the prior disadvantages.